Effects of Trichoderma harzianum Strains on Seedling Quality of Tomato

This study was conducted to determine the effects of Trichoderma harzianum on seedling growth and quality as two consecutive experiments during the spring months of 2018. In the first experiment, four different T. harzianum strains and a commercial preparate were used by adding into seed sowing substrate and compared with control group which had no treatment. The most promising strain (strain2), was used with and without foliar fertilizer (20:20:20) and foliar fertilizer itself was considered as control. Emergence period and rate were determined to observe the effects of treatments of germination of seeds. Regarding the seedling growth and quality, seedling length, root length, hypocotyl diameter, leaf thickness, fresh and dry weights of root and shoots, dry matter content, color, chlorophyll index, leaf macro and micro plant nutrient contents and seedling quality index were determined at the planting stage. Data obtained from the first experiment showed that the effects of T. harzianum strains on seedling morphology, physiology and nutrient content were different. Among the tested strains, strain2 showed better performance on seedling length, root and shoot dry matter contents, total fresh weight, chlorophyll, a color value and P, Ca, Mn, Cu and Zn contents of leaves and improved seedling quality. The second experiment result showed that the foliar fertilizer application increased the efficiency of T. harzianum strain2. T. harzianum strain2 without foliar fertilizer remained below the control treament in all measured parameters. When all the data were evaluated together, it was concluded that T. harzianum could be used to increase seedling quality due to its positive effects on seedling biomass, plant nutrition uptake and quality index. Moreover, it can be used in organic seedling production as alternative biostimulant.